Pilot operated valve



Aug. 28, 1951 E. J. DILLMAN 2,566,173

P-ILOT OPERATED VALVE H Filed Nov. 23, 1949 2 Sheets-Sheet 1 HEAT ExcHANcER IN VEN TOR.

BY ww M M ATTORNEY Aug. 28, 1951 l E. J. DILLMAN 2,566,173

' PILOT OPERATED VALVE Filed Nov. 25, 1949 I ZSheetQ-Sheet 2 I i 44 r 34 a7 a9 as g Y YINVENTOR. FIG. 2 BY M K M 14440 ATTORNEY Patented Aug. 28, 1951 PILOT OPERATED VALVE Earnest J. Dillman, Detroit, Mich., assignor to Detroit Lubricator Company, Detroit, Mich, a corporation of Michigan Application November 23, 1949, Serial No. 129,011

:4 Claims. 1

This invention relates to new and useful improvements in pilot operated valves and more particularly to thermostatically actuated pilot operated valves.

One of the objects of this invention is to provide a pilot operated valve of new and improved construction.

Another object is to provide a pilot operated valve of the modulating type and thermostatically actuated.

.Another object is to provide a pilot operated valve characterized by its simplicity and ease of manufacture and assembly.

Other objects will become apparent from time to time throughout the specification and claims as hereinafter related.

This invention comprises the new and improved construction and combination of parts to be described more fully hereinafter and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawings to be taken as part of this specification there is clearly and fully illustrated a preferred embodiment of this invention in which drawing:

Figure 1 is a more or less diagrammatic view of an air conditioning system having positioned therein the valve forming the subject of this invention, and

Fig. 2 is a sectional view of the valve and power element therefor shown in Fig. 1.

Referring to the drawings by characters of ref erence there is shown in Fig. 1 and air conditioning system preferably of the cooling type but which could be easily adapted for heating operation. In this system there is provided a heat exchange coil l for heating or cooling a space generally designated as 2. with heat exchange fluid by an electrically operated circulating pump 3. The pump 3 discharges through a conduit 4 to a heat exchanger shown diagrammatically as 5 which heats or cools the fluid which is to be supplied to the coil ll. The heat exchanger 5 is connected as by a conduit 6 to the inlet of a three-way flow controlling valve 1. The valve 1 has two outletsone of which is connected to a conduit 8 leading to the cooling coil l and the other of which is connected to a bypass conduit 9 which is. connected by a T connection as at It to the return conduit to the circulating pump 3. The valve 1 has a thermostatic power element arrangement having a temperature responsive bulb element generally designated as H responsive to the temperature of the space 2 to control the flow of cooling water by the valve The coil 1 is supplied 2 'l to the cooling coil I. In Fig. 2 the valve 7 and power element H are shown in section and illustrating the various details of construction. The valve 7 comprises a casing l2 having an inlet passage 13 and a pair of outlet passages l4 and I5. Within the casing I there are a pair of spaced partitions l6 and ll having valve ports [8 and I9 communicating with the outlet passages l4 and 15 respectively. On the outlet side of the valve ports 18 and Hi there are valve members 20 and 2| respectively which are spaced by an interconnecting stem member 22 to permit alternate opening and closing of the ports 18 and IS. The valve member 2| has a stem portion 23 extending into the outlet passage l5 and guided in a guide sleeve member 2% which is screw-threadedly secured adjacent the outlet end of the passage I5. There are provided flanged annular disc members 25 and 26 which seat on annular shoulders on the valve stem projection 23 and guide sleeve 24 respectively and which secure therebetween a spring 27 urging the valve member 2! to close its port Ill. The valve member 20 has a plug portion 28 which extends into the port l8 and which is operable to provide a restriction when the valve member 20 is in open position. The valve port it opens into an end cavity 29 in the casing 12 which is open to the outlet passage I4 and which has at its upper end portion a circular recess generally designated as 39. A power element casing 3| is provided and secured to the valve casing I2 to close the end cavity 239 and recess 30. The power element casing 3| has a circular recess 32 therein which is closed by a diaphragm 33 of rubber or rubber-like material. The diaphragm 33 is secured at its outer periphery against the casing 3| by a dish-shaped closure member 34, the closure member 34 also extending into the circular recess at the end of the valve casing 12 and seating on an annular shoulder therein. The valve member 20 has a valve stem formed in two sections 35 and 36 respectively and connected by a dowel and recess connection. The valve stem portion 36 is guided through an aperture 31 in the dish-shaped closure member 34 and has its upper end portion extending through the diaphragm 33. There are provided upper and lower clamping plates 38 and 39 on opposite sides of the diaphragm 33 and positioned on the valve stem portion 35, the clamping plates 38 and 39 being tightened. as by a nut 40 to provide a tight seal around the valve stem portion 36. The power element casing 3| has a threaded end aperture M in which is positioned a threaded sleeve member 42 and adjustment member .3. l'he adjustment member 43 is aligned with the end of the valve stem portion 36 and is operable to be moved into engagement therewith manually to provide an auxiliary manual valve operating means. The threaded aperture 4| is closed by a cap member M covering the end of the adjustment member 43. The valve casing it! has a passage 35 extending from the inlet passage is and registering with passage 46 in the power element casing 3i opening into a chamber ll formed by a threaded aperture or passage L8 in the casing 3 i. There is a valve port and seat member 49 defining one end of the chamber Ill and closed by a valve member 5!) which is held by a spring 5! in closed position. The valve port which is closed by the valve member 5& is communicable through a passage 52 with the space enclosed by the recess 32 and diaphragm 33. There is an outlet or bleed passage 53 in the casing 3! which extends from the recess 32 and registers with the passage 58 in the valve casing l2 and opening into the outlet or bypass passage l4. A threaded member 55 having an orifice 55 of predetermined size is positioned in the passage E l adjacent the bypass outlet passage i l. A sleeve member 51 is threadedly secured and sealed in the end of the passage 58 in the casing member SI and has guided therein a plunger 58 having a rod portion 59 engageable with the valve member 50 for actuation thereof. A sealing diaphragm 6B is secured to the sleeve member 57 and the plunger 58 to prevent leakage from the chamber 47. At the outer end of the valve actuating plunger 58 there is provided a hat-shaped diaphragm [ll of rubber or rubber-like material which surrounds the end of the plunger and which is secured at its periphery against the end. of the sleeve member 5? by a hollow cup-shaped casing member 82. The diaphragm 8i and hollow casing member 2 define a power element chamber, the operation of which will be set forth more fully hereinafter. There is a tube or conduit member 63 which opens into the end of the cupshaped casing member 62 and is sealed therein by soldering as at 64. The other end of the tube 63 is secured in a casing member 65 forming a part of the power element bulb H. The casing member 65 has a longitudinal passage E56 opening into a cup-shaped recess Gl which is closed by a hatshaped diaphragm 68 and secured in position by a sleeve member 69. the sleeve member 69 and fits into the hat-shaped diaphragm $8. The plunger 70 is connected by a rod ll to another plunger 12 carried in a cylindrical sleeve member 13 and urged in a direction restricting the size of the chamber 6'! by a spring 14. The sleeve member 73 has a plug 15 at its end which has a recess receiving one end of an adjusting rod 16, the other end of which is secured in a threaded adjustment member designated as T1. In the casing member 65 there is a passage opening laterally from the passage 66 in which is secured one end of a tubular bulb element 78 which bulb element is coiled within the supporting casing 79 and the adjusting mechanism just described. The bulb element i8, chamber 8'1, tube 83 and cup-shaped casing 52 form a power element system which is filled completely with a thermally expansive liquid such as oil for actuation of the hat-shaped diaphragm BI and plunger 58.

In operation this invention functions generally as follows:

The valve 1 is arranged with the inlet passage I3 connected to the conduit 6 leading from the heat exchanger 5. The outlet passage i5 of the A plunger ill is guided in r valve is connected to the conduit 8 leading to the heat exchange coil and the passage I4 is connected to the bypass conduit 9. When the valve is in an inactive position the spring 21 is operable to hold the valve member 2! in a closed position relative to its port l9 and the valve member 23 in open position relative to its port I8 thus permitting fluid to flow through the bypass conduit 9 directly back to the circulating pump 3. In this position the restricting plug 28 in the valve port H3 is operable to cause pronounced pressure drop through the port so that the pressure in the cavity 29 and outlet passage M is considerably lower than that in the inlet l3 of the valve. Liquid outlet pressure is open to the underside of the diaphragm 33 through apertures 34 in the cupshaped closure member 34. The power element arrangement shown for operating the pilot valve member 50 is designed to operate on rise of temperature to control flow of cooling water to the cooling coil I. Upon rise in temperature of the space 2 being cooled by the coil 5 the liquid in responsive bulb element 78 will expand thus transmitting movement through the hat-shaped diaphragm iii to move the plunger 53 and rod 59 to move the valve member 50 to open position. As the valve member 5E3 is moved toward open position liquid at inlet pressure is permitted to flow through the passages 35 and 36, the valve port and seat member IE9 and aperture 52 into the recess 32 in the casing 3i. The liquid which is supplied to the recess 32 is permitted to flow outward therefrom through the bleed passages 53 and 54 and orifice 56. When the pilot valve member 50 is opened a sufficient amount so that the liquid flowing into the recess 32 exceeds the rate at which it is then flowing from the orifice 55, the pressure in the recess 32 begins to increase upon the upper side of the diaprragm 33 and the diaphragm is moved downward in accordance with the differential of pressure between that in the recess 32 and the pressure on the outlet side of the valve member 28. If the pilot valve member 50 is opened suihciently far, the pressure differential across the diaphragm 33 will be such as to move adjustment of the threaded adjustment member 7'! the cylinder 73 and rod H may be moved thus permitting, movement of the hat-shaped diaphragm 68 upon initial thermal expansion to increase or decrease the volume of the power element system and thus vary the temperature of response for actuation of the valve 50. It will be obvious that as the position of the pilot valve member 56 is modulated by changes in temperature of the bulb element 78 the pressure differential across the diaphragm 33 will likewise be modulated thus to vary the extent of opening of the valve members 20 and 2 I.

If there should be a rupture or other form of leakage some place in the power element system so that the pilot valve member 50 cannot be operated automatically in response to temperature, the spring 27 will cause the valve members 20 and 2| to assume the initial inactive position as shown with the passage to the coil closed and that to the bypass opened. If, during such a condition of power element failure, it is desired to actuate the valve to permit flow of cooling liquid to the cooling coil, the cap member 44 may be removed from the power element casing 34 and the adjustment member as turned down manual- 1y to engage the end of the valve stem portion 36 and forcibly move the valve members to an actuated position.

It should be noted that by the construction set forth herein entire power element casing 3|, diaphragm 33 and closure member 34 and upper valve stem portion 36 may be removed from the valve casing l2 as a unit for repair or replacement without requiring complete disassembly of the valve.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent of the United States is:

1. In a heating or cooling system of the type having a heat exchange coil and a bypass, a valve for controlling flow of heat transfer fluid to the coil or to the bypass, comprising a valve casing having an inlet passage and a pair of outlet passages, a pair of spaced partitions within said casing having valve ports communicable one with each of said outlet passages, said inlet passage opening into the space between said partitions, said casing having a cavity at one end intercommunicating one of said outlet passages and one of said valve ports, a power element casing secured to said valve casing and closing said cavity, a pair of valve members cooperable one with. each of said valve ports to control flow alternately through said ports, a valve stem common to each of said valve members, a spring cooperable with said valve stem and urging the same in a direction opening said one valve port and closing the other valve port,

said power elementcasing having a cavity ad-.

jacent' said first-named cavity, a flexible diaphragm extending across and sealing said last named cavity and secured to one end of said valve stem, a passageway extending through said casings from said inlet passage to said lastnamed cavity for supplying liquid at inlet pressure thereto, a valve port in said passageway in said power element casing, a valve member cooperable with said last-named port to control the application of liquid inlet pressure to said diaphragm,'athermostatic power element in said power element casing responsive to changes in external temperature for moving said last-named valve mem'ber; said power element including a plunger having a rod portion engageable with said last-named valve member, a hat-shaped diaphragm surrounding one end of said plunger, a hollow casing member secured to said power element casing against the periphery of said hat shaped diaphragm and defining a power element chamber, a tubular bulb element and tube connected to said casing member and opening into said chamber, a member enclosing a chamber connected to said power element tube, a movable wall member in said last-named chamber adjustably movable to determine the volume of the power element system defined by said chambers, said bulb element and tube, and said power element system being completely filled with a thermally expansive liquid; an outlet bleed passageway through said casings from said last-named cavity to said one outlet passage, and said power element being operable upon opening movement of said last-named valve member to cause liquid at inlet pressure to be applied to said diaphragm to move said valve members 6 in a direction closing said one valve port and opening the other port.

2. In a heating or cooling system of the type u having a heat exchange coil and a bypass, a valve for controlling flow of heat transfer fluid to the coil or to the bypass, comprising a valve casin having an inlet passage and a, pair of outlet passages, a pair of spaced partitions within said casing having valve ports communicable one with each of said outlet passages, said inlet passage opening into the space between said partitions, said casing having a cavity at one end intercommunicating one of said outlet passages and one of said valve ports, a power element casing secured to said valve casing and closing said cavity, a pair of valve members cooperabl one with each of said valve ports to control flow alternately through said ports, the valve member closing said one valve port having a plug portion extending into said port to provide a restriction when the port is opened thereby to cause a pronounced pressure drop between said inlet passage and saiclone outlet passage, a valve stem common to each of said valve members, a spring cooperable with said valve stem and urging the same in a direction opening said one valve port and closing the other valve port, said power element casing having a cavity adjacent said first-named cavity, a flexible diaphragm extending across and sealing said last-named cavit and secured to one end of said valve stem, a passageway extending, through said casings from said inlet passage to last-named cavity for supplying liquid at inlet pressure thereto, said diaphragm being responsive' to the differential between liquid at inlet pressure on one side and the pressure of liquid in said one outlet passage on the other side, a valve port in said passageway in said power element casing, a valve member cooperable with said last-named port to control the application of liquid inlet pressure to said diaphragm, a thermostatic power element in said power element casing responsive to changes in external temperature for moving said last-named valve member; said power ele merit including a plunger having a rod portion engageable with said last-named valve member, a hat-shaped diaphragm surrounding one end of said plunger, a hollow casing member secured to said power element casing against the periphery of said hat-shaped diaphragm and defining a power element chamber, a tubular bulb element and tube connected to said Casing member and opening into said chamber, a member enclosing a chamber connected to said power element tube, a movable wall member in said last-named chamber adjustably movable to determine the volume of the power element system defined by said chambers, said bulb element and tube, and said power element system being completely filled with a thermally expansive liquid; an outlet bleed passageway through said casings from said lastnamed cavity to said one outlet passage, said power element being operable upon opening movement of said last-named valve member to cause liquid at inlet pressure to be applied to said diaphragm to move said Valve members in a direction closing said one valve port and open ing th other port, and a. threaded abutment member carried by said power element casing in line with said one end of said valve stem and engageable with said valve stem to provid a man ually operable means for closing said one valve port in the event of power element failure.

3. In a heating or cooling system of the type having a heat exchange coil and a bypass, a

' 7 valve for controlling flow of heat transfer fluid to the coil or to the bypass, comprising a valve casing having an inlet passage and a pair of outlet passages, a pair of spaced partitions within said casing having valve ports communicable one with each of said outlet passages, said inlet passage opening into the space between said partitions, said casing having a cavity at one end intercommunicating one of said outlet passages and one of said valve ports, a power element casing secured to said valve casing and closing said cavity, a pair of valve members cooperable one with each of said valve ports to control flow alternately through said ports, the valve member closing said one valve port having a plug portion extending into said port to provide a restriction when the port is opened thereby to cause a pronounced pressure drop between said inlet passage and said one outlet passage, a valve stem common to each of said valve members, a spring cooperable with said valve stem and urging the same in a direction opening said one valve port and closing the other valve port, said power element casing having a cavity adjacent said firstnamed cavity, a flexible diaphragm extending across and sealing said last-named cavity and secured to one end of said valve stem, said valve stem comprising tw sections interconnected by a dowel and recess connection permitting removal of said power element casing, diaphragm, and one valve stem section without further disassembly of the valve members, a passageway extending through said casings from said inlet passage to said last-named cavity for supplying liquid at inlet pressure thereto, said diaphragm being responsive to th dilierential between liquid at inlet pressure on one side and the pressure of liquid in said one outlet passage on the other side, a valve port in said passageway in said power element casing, a valve member cooperabl with said last-named port to control the application of liquid inlet pressure to said diaphragm, a thermostatic power element in said power element casing responsive to changes in external temperature for moving said last-named valve member; said power element including a plunger having a rod portion engageable with said lastnamed valve member, a hat-shaped diaphragm surrounding one end of said plunger, a hollow casing member secured to said power element casing against the periphery of said hat-shaped diaphragm and defining a power element chamber, a tubular bulb element and tube connected to said casing member and opening into said chamber, a member enclosing a chamber connected to said power element tube, a movable wall member in said last-named chamber adjustably movable to determin the volume of the power element system defined by said chambers, said bulb element and tube, and said power element system being completely filled with a thermally expansive liquid; an outlet bleed passageway through said casings from said last-named cavity to said one outlet passage, said power element being operable upon opening movement of said last-named valve member to cause liquid at inlet pressure to be applied to said diaphragm to move said valve members in a direction closing said one valve port and opening the other port, and a threaded abutment member carried by said power element casing in line with said one end of said valve stem and engageable with said valve stem to provide a manually operable means for closing said one valve port in the event of power element failure.

4. A removable power element structure adapted for use with a control valve, comprising a power element casing having a central recess opening on one side thereof and having a surrounding shoulder, a flexible diaphragm extending across said recess and having its periphery seated on said shoulder, a valve stem having one end extending through and sealed in said diaphragm for movement thereby, a dish-shaped closure member fitting said recess and compressively engaging said diaphragm to hold the periphery thereof sealed against said shoulder, said closure member having a central aperture re ceiving and guiding said valve stem, a passageway extending laterally in said casing and opening at one end into said recess, a second passageway operable as a bleed and opening through said casing from said recess, a third passageway operable as an inlet to said first-named passageway, a valve seat member defining a valve port in said first-named passageway, a valve member closing said port, a power element for actuating said valve member and threadedly secured in the other end of said first-named passageway, said power element comprising a threaded guide sleeve member, a plunger reciprocally movable in said sleeve member and engageable with said valve member for actuation thereof, a hat-shaped diaphragm surrounding one end of said plunger, a hollow cover member securing the periphery of said hat-shaped diaphragm against the end of said sleeve member and defining therewith a power element chamber, a tubular bulb element and tube connected to said cover member and opening into said chamber, means comprising an adjustable chamber connected to said power element tube and operable to determine the volume thereof, said power element, tube and bulb element being completely filled with a thermally expansive liquid, and a threaded abutment member carried by said casing and alined with one end of said valve stem and engageable therewith to provide a manually operable means for moving said stem in the event of power element failure.

EARNEST J. DILLMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 236,520 Westinghouse Jan. 11, 1881 1,327,675 Hornung Jan. 13, 1920 1,756,688 Hutchinson Apr. 29, 1930 2,457,618 Wiesendanger Dec. 28, 1948 FOREIGN PATENTS Number Country Date 414,397 France Sept. 1, 1910 OTHER REFERENCES Instrumentation, a magazine published by the Brown Instrument Company, Philadelphia, Pennsylvania, pp. 13 through 17, of vol. 2, No. 4 (January-February 1947). 

